By Anne Fischer Stausholm, landscape architect and member of PLR (Danish Practicing Landscape Architects Council).

If you like to putter about with your plants, but do not think the cultivation of cucumbers and tomatoes in the greenhouse is something for you, then maybe you should consider an orangery. They have become more and more popular in recent years. Previously, orangeries were reserved for the upper class, because they were so expensive. Today, orangeries come in all sizes and different price ranges. Their origin goes back to the 18th century when Europe’s aristocracy was particularly keen to grow citrus trees. Orangeries were built at great castles and manor houses, where the many exotic pot plants, especially citrus trees that could not tolerate the cold winter, were stored indoors. They were often large high-ceilinged brick buildings with natural light from the south. When the plants were moved outdoors in summer, the orangery was often used for various summer events.

The most impressive example of an orangery is undoubtedly at Versailles, the Sun King, Louis XIV's chateau in France just outside Paris. It was built in 1674 and is considered more beautiful than the castle itself. Even today it is the winter storage place for all sorts of oriental plants, such as citrus, figs and peaches. In summer, the plants give a lavish and impressive expression to the park. In no way can we compare with this, but Denmark also boasts an orangery at a royal palace. Fredensborg Palace has an extremely beautiful Orangery, which is more recent and is open to the public during the summer. It was built in 1995 and has exactly the same function as before. The large pot plants that stand in the palace’s kitchen garden in the summer will be kept here in the winter.

What characterizes an orangery?

It is debatable where the line is between an orangery, a greenhouse and a hothouse. An orangery is a heated and insulated hothouse where plants that cannot tolerate freezing temperatures or low temperatures may overwinter. It is based on the plant’s requirements and if it is relatively cold in winter, it corresponds to the requirements of traditional orangery plants. An orangery is a combination of cultivation, storage and habitation united in a higher aesthetic whole. Typically, an orangery is beautiful, classic, with a high ridge and often made from good and solid materials. It is of course a matter of taste how fine it should be, but the aesthetic dimension is undoubtedly linked to the function associated with people who see it as an enjoyment of life pottering about their plants and enjoying the beauty by moving around them. How do royal palaces, aesthetics and enjoyment of life fit into modern everyday Danish life? Yes, this is where it gets interesting.

The number of garden enthusiasts in Denmark is increasing and we talk more and more about the therapeutic effect of working in the garden. We have outdoor kitchens, outdoor baths, Jacuzzis and hammocks, and we have many pots, actually incredibly many in proportion to how much tendering they require. It is also costly to plant and replace the plants in all these pots and moreover exotic plants are popular - olive trees, citrus trees, etc. So maybe the step is not that far to an orangery that can extend the gardening season and be used both in summer and winter.

How is an orangery constructed?

The size of an orangery is immaterial. The orangery at the Palace of Versailles is, for example, 155 m long and consists of an additional two wings. In its heyday, there were 1,200 orange trees in pots of silver, plus 300 different exotic trees. Today in winter there is up to 1,200 trees in tubs. But less will do. Most importantly, is that there is a relationship between the other buildings and the size of the plot where the orangery is to be placed.

The orangery’s size should naturally fit the number of plants that will be in the orangery and there can very quickly be many, because there is much to choose from. Ideal plants for an orangery are, for instance, citrus, camellias, myrtle, oleander, hibiscus, geraniums, agapanthus, orchids, figs, palms and olive trees.

It is better to make the orangery a little smaller and then have the energy to refine both plants and equipment. Wood, tiles and glass in combination with masonry are typically seen in an orangery and there must be certain symmetry, indicating the classical relationship.

The first orangeries did not have the advantage of cast iron and aluminum. They were built of brick with glass panels. The lighter constructions offer several options and combined with modern technology, with control of heat and moisture, it altogether provides better conditions for the plants. The aluminum profiles are lower maintenance than wood and are available in a variety of colors. The classic English dark green is the traditional color for orangeries. Remember to allow for plenty of height in the orangery, as it helps to even out sudden heat/cold changes and provides a good microclimate, as well as looking beautiful. Height also applies to the doors. It's hard to get large pots with olive trees in through a narrow and low glass door without damaging the plants. Double doors can also be an idea, where you can then achieve a closer contact between the garden and orangery in the summer.

The orangery can be built connected to the house or free standing, but it is important that the control of humidity and heat can be controlled or else the plants will die. It should be possible to heat the orangery up, but it should also not be too hot as typical orangery plants cannot tolerate it. A couple of degrees in winter are enough to ensure the plants' survival.

It is practical if the orangery runs with some automation in the form of automatic window opening. The window’s surface can be big to give the plants the most light. Single pane windows can cause some problems and are expensive on the heating bills in a cold winter when the orangery has to be kept frost free. A sealed glazing unit does not work as designed and requires the possibility of good airing, which may be especially needed in the spring. Moreover, the glazing bars are too wide. Single layer windows with double glazing are preferable.

If you choose an orangery predominantly in glass, a low wall will help to give it a classic look, make it more proportionate and reduce it being characterized as a greenhouse. The masonry can both screen against a hard north or west wind and it may also reflect and absorb sunlight and thus help to create a good indoor climate. Stone is the original solution to the floor surface. A floor, most often in pale yellowish colored tiles is the classic orangery solution and also has the advantage that it can withstand getting wet in contrast to a wooden floor. Finally, it can be a good idea to mount gutters and downspouts. It prevents splashes on the masonry and glass. In return, you must have water in the orangery. Water as fountains and stationary tubs are classic garden features and in garden art has been a symbol of life. It is also a beautiful and practical measure in the orangery.

When spring comes and the heat takes hold, it is time for you to move the plants from orangery. They should then preferably be in the shade before being placed in direct sunlight, so the leaves do not scorch.

In principle, the orangery is empty during the summer and it is therefore important to account for these six months in the planning. An orangery must also function in summer and of course there may be pots of geraniums, rosemary and many other things. However, it is also the time when it might be a wonderful place to spend the cool summer nights or cold summer days. So think about space to sit in the planning of your orangery. It can also be a nice place to work potting plants, so seed and prick out in early spring. But remember that too much plastic and garden equipment will spoil the orangery’s refined expression.